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Building Technologies
Basic Documentation LMV5...
CC1P7550en
19 O2 trim control with LMV52 and PLL52
22.05.2018
19.4.9 Increasing the manipulated variable in case of
fast
load
changes
(
O2ModOffset
, formerly
O2Offset
)
When changing the load under unfavorable setting conditions, it could happen that the
actual O2 value drops below the O2-min-limit.
In order to prevent this, the user can use parameters to set an offset for the O2 value in
the event that a
fast
load change occurs.
One increase is made depending on how
fast
the load change is (for definition of
fast
refer to chapter
Behavior in the event of load changes
).
The next increase can only be made once the locking time for the load change has
elapsed (waiting time of 2 x
Tau current load
).
There will be no increase of the O2 value when O2 trim control is deactivated.
The parameter defines the increase of the O2 value in %.
Example:
O2ModOffset
= 0.5%, O2 actual value 1.4%
In the event of fast load change, the O2
value reached will be 1.9%.
Actual O2 value
O
2
M
o
d
O
ff
se
t
1.4%
1.9%
O2 setpoint
7550d39e/1012
Figure 119: Increasing the manipulated variable in the case of a load change
Parameter
Gas:
O2ModOffset
Oil
: O2ModOffset
